Revised vim integration: vcsbzr.vim

[Neil Martinsen-Burrell]

Vim's generic VCS integration plugin is VCSCommand.  Sabin Iacob posted here
that he had written an initial VCSCommand plugin for bzr support.  I've modified
his original to be a bit more bzr specific and reposted it to the VCSCommand
enhancement request where Sabin initially posted his version:
http://code.google.com/p/vcscommand/issues/detail?id=7

This streamlines some of the buffer identification code, replaces info with
version-info and makes lock/unlock no-ops for bzr.

Hopefully the authors of VCSCommand will integrate this plugin into their system
soon.  Otherwise, it would be reasonable to host this on Launchpad under the bzr
team as part of efforts to improve IDE integration.

-Neil